Research operations are conducted by establishing a panel of participants, often referred to as panelists. In some research operations, the panelists are provided with portable monitoring devices to gather research data. In other research operations the panelists' own portable devices are employed to gather research data. In either case, the panelists are instructed to carry the portable devices with them during the day for gathering research data, such as data indicating exposure to media and/or other market research data.
Those who pay to use such market research data want to be assured that the data is reliable. In particular, if the portable monitor was not actually carried about by a panelist during the day, whatever data has been collected by the portable monitor does not reflect the experience of a panelist. Accordingly, those who pay for use of such research data want reasonable assurances from the research organization that the portable monitors used to gather the data have actually been carried about by individuals or at least accompany individuals during the times that research data is collected by such monitors.
Arbitron Inc., which pioneered the use of portable monitors for gathering research data, has developed and implemented techniques to provide such assurances to those who license its research data. Such techniques are the subject of U.S. Pat. No. 5,483,276 issued Jan. 9, 1996 in the names of Brooks, et al., which is owned by the assignee of the present application and is hereby incorporated herein by reference in its entirety.